| With the development of people’s economic and living standards,mechanical refrigerator cars are the mainstay for transporting the fresh food,and their performance will directly affect the development of our country’s cold chain.The working performance of air conditioning ventilation system will directly influence uniformity of internal flow field.This article uses CFD technology to optimize the outlets’ layout in the mechanical refrigerator car and provides technical support for domestic design of mechanical refrigerator car.This article takes the mechanical refrigerator car as the research object and chooses κ-εstandard turbulence calculation model and SIMPLE algorithm to evaluate temperature field of the air duct and cargo area in the refrigerator car.The main work includes:(1)Taking the cold tomatoes as the research object,using the porous media theory to establish the mathematical model of tomato,simulating the flow field under the circumstances of unilateral and bilateral ventilation,and comparing and analyzing the results.(2)Under the circumstance of bilateral ventilation,to simulate its no-load and full-load four conditions and to analyze flow field in the car and get the law of the distribution of outlets’ influence on the uniformity of the temperature in the cargo area,then design the optimized plan of outlets’ layout.(3)Under the circumstance of unilateral ventilation,to simulate its no-load and full-load two conditions and evaluate the flow field in the car.The results show:(1)Under the circumstance of unilateral ventilation,the maximum flow pulsation rate of outlet is 22.58%,much higher than 11.32%of bilateral ventilation.It means that outlets have a bigger fluctuation and a worse uniformity of temperature flow field in every section than unilateral ventilation.(2)When the central outlets are closed,cargo area’s temperature ranges from 6.18 to 10.73℃,and uniformity of temperature field is poor,therefore it is better to make the outlets which located in the middle of the car open.(3)Under the circumstance of original plan,temperature in the cargo area ranges from 7.64 to 8.72℃,and for optimized plan,it ranges from 7.67 to 8.37℃,so optimized plan has a smaller temperature difference and a better uniformity of temperature distribution. |
